My first try was an ignominious loss. Had barely the slightest idea what to do except lay smoke and advance on several fronts toward the objectives. Didn't seem to be enough time for anything too fancy. So I got slaughtered. As DRG (Don) mentioned, this scenario wasn't meant to be easy (his hint concerning the northern force provided a key that helped cut this Gordian Knot: http://forum.shrapnelgames.com/showthread.php?t=48886.)

Assaults are usually more difficult; maybe that's why most players prefer meeting engagements :-). The basic idea is to lay smoke to cover your advance, bring up engineers/sappers/pioneers to clear or find a path through mines and obstructions, bombard the intended sector of breakthrough, then pour through.

But of course the devil is in the details. (In the gameplay section of the SPMBT manual there's a section which gives pointers on neutralizing defenders which may be helpful: "Strategy for taking out big AT guns [and other nasty things like that...])". And I'm pretty sure the exact strategy and tactics used to solve this scenario wouldn't work for all scenarios, or even this one on another try--luck has more than a little to do with it!

Yes, experience made a huge difference; after getting beaten up eight or ten times you're gonna be looking in all directions, considering more angles, and so on. It helps that you can start all over again, like Tom Cruise in Edge of Tomorrow.

And without that tip about the northern force--one of whose units took the easternmost trench objective--a decisive win would have been considerably more difficult. Perhaps that's the "certain way" you mentioned, although maybe the main force could've done it on their own. With a little luck...